Conventional fiber optic gyroscopes utilize a glass or plastic core fiber to create the looped optic coil. Light is transmitted through each end of the fiber coil and a phase shift between the two light waves can be measured through interferometry. Specifically, due to the Sagnac effect, if the gyroscope is rotated in a given direction, the wave travelling against the direction of rotation experiences a shorter travel path. Thus, a phase shift occurs between the two waves, which can be measured with an interferometer.
Glass core fiber optic gyroscopes, however, have distinct disadvantages. First, the glass in the gyroscope is temperature sensitive. More specifically, if the gyroscope is exposed to changing temperatures, the physical characteristics, such as length, of the glass core fiber changes thereby affecting the operation of the gyroscope. Another disadvantage is that the glass is susceptible to the environment in space. In space the glass is exposed to radiation, magnetic fields, etc. that also affects the physical characteristics of the glass. More specifically, the space elements cause the glass core to twist, thereby affecting the operation of the gyroscope.